[Distutils] How to upgrade distribute with distribute_setup if necessary?

[anatoly techtonik]

I can't install Sphinx in a Python 3.2 directory with distribute
0.6.13 installed due to a bug in outdated distribute. Sphinx uses
distribute_setup.py and if no setuptools installed it fetches new
version where there is no such problem. The check is the following
code:

try:
    from setuptools import setup, find_packages
except ImportError:
    import distribute_setup
    distribute_setup.use_setuptools()
    from setuptools import setup, find_packages

What is the proper way to modify it to make distribute_setup.py
upgrade distribute if necessary?
--
anatoly t.